The FBI and the U.S. Marshals Service said Curtis was taken into custody at 5:15 p.m.

In addition to President Obama, Curtis also sent ricin-laced letters to Sen. Roger Wicker (R-Miss.) and a Mississippi justice official.

The FBI said that the poisonous letters had nothing to do with the Boston Marathon bombing, even though a bomb squad was deployed to ensure that an explosion was not a concern.

As previously reported by NewsOne, Secret Service spokesman Edwin Donovan said that the letter was detected at an off-site screening facility under the protection of the Secret Service:

“This facility routinely identifies letters or parcels that require secondary screening or scientific testing before delivery,” the Secret Service said in a statement. “The Secret Service White House mail screening facility is a remote facility, not located near the White House complex, that all White House mail goes through.”

CDC defines ricin as follows:

“Ricin works by getting inside the cells of a person’s body and preventing the cells from making the proteins they need. Without the proteins, cells die. Eventually this is harmful to the whole body, and death may occur.”

Only a small amount of ricin needs to be ingested for it to be deadly.

Curtis was arrested at his Mississippi home about 100 miles from Memphis.